AWS serverless A2A gateway replaces 190 point-to-point agent connections with one entry

As enterprises deploy AI agents across teams and infrastructure, managing agent-to-agent communication becomes an operational burden. Without a centralized layer, each new agent adds point-to-point connections, separate credentials, and custom routing logic. A deployment of 20 agents can require up to 190 point-to-point connections, leading to quadratic scaling of overhead. Access control becomes fragmented, and teams waste engineering cycles on connectivity instead of building agent capabilities. The serverless A2A gateway pattern solves this by placing a single entry point in front of all agents, regardless of runtime (Amazon ECS, Lambda, Bedrock AgentCore, or non-AWS clouds).

The architecture uses Amazon API Gateway (REST) as the entry point, supporting SSE streaming for real-time responses. A Lambda authorizer validates JWT scopes (e.g., billing:read) and generates IAM policies to allow access to specific agent paths. DynamoDB stores an Agent Registry, Permissions table, and rate-limit counters. Amazon Cognito handles OAuth 2.0 client credentials flow, while Secrets Manager secures backend credentials. For semantic search, agent descriptions are embedded using Amazon Titan Text Embeddings and stored in S3 Vectors, enabling natural language discovery. The gateway supports both JSON-RPC and RESTful A2A endpoints, and clients can discover agents via the /agents endpoint. Powered by Terraform, this solution provides a production-ready foundation for scalable, secure multi-agent workflows.